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SteveKing
10-09-2015, 08:57 AM
Anyone know what size drill hole I'd need to get a 1.25" npt to thread into my UDS? I'm wondering if this will get the job done: http://www.harborfreight.com/2-piece-titanium-nitride-coated-high-speed-steel-step-drills-96275.html

Q Junkie
10-09-2015, 09:03 AM
1-1/4" pipe has an outside diameter of just over 1-1/2"
A hole saw would work better

SteveKing
10-09-2015, 09:34 AM
I don't care for using hole saws, they can be sloppy if you aren't super precise. Has anyone ever used a knock out punch on a rounded surface like a uds?

ITBFQ
10-09-2015, 09:35 AM
I used those exact bits from Harbor Freight to make mine, and they worked great. Just take your time.

SteveKing
10-09-2015, 09:37 AM
I used those exact bits from Harbor Freight to make mine, and they worked great. Just take your time.


Me too, but I don't think it will fit a 1-1/4 NPT pipe.

ITBFQ
10-09-2015, 09:43 AM
http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html

Looks like you'd be short 1/8 of an inch. I bet if you'd just bang the bit around (carefully, of course) in the hole, you can get it to widen the other 1/8 inch you need no problems.

long haired hippie
10-09-2015, 10:58 AM
1.484" hole (1 31/64").
That said, you'd be better off with a nps fitting.
For 1 1/4-7 use a 1 7/64" bit.
For 1 1/4-12 use a 1 11/64" bit.

I do this stuff for a living, I'm a machinist.

jermoQ
10-09-2015, 10:18 PM
I don't care for using hole saws, they can be sloppy if you aren't super precise. Has anyone ever used a knock out punch on a rounded surface like a uds?

I have never used a knockout punch on a round surface. You should be able to use that as electric boxes are similar thickness but I am not sure about the material? A drum is steel....may be harder than the stuff used to make an electrical panel. Not sure though.

punchy
10-09-2015, 10:30 PM
would think knockout would try to straighten metal around your hole and make it distorted. but I never tried it.

BBQ Freak
10-09-2015, 10:50 PM
I bought this hole saw at Ace Hardware and it would cut a exact hole for $15 , the drill bit in the middle helps guide it but I do not know what size you need but just ask them . ignore the other stuff in my pic :wink:

http://img.photobucket.com/albums/v199/TwiztidOne/Brinkmann%20Cimarron%20Offset%20Smoker/DSCF6244.jpg

DouG M
10-10-2015, 08:00 AM
Anyone know what size drill hole I'd need to get a 1.25" npt to thread into my UDS? I'm wondering if this will get the job done: http://www.harborfreight.com/2-piece-titanium-nitride-coated-high-speed-steel-step-drills-96275.html

No that will not do a hole big enough your 1.25 pipe but will do alright for a 1" pipe. That being said why do you want to use 1.25 pipe as to a .750 pipe if this for your intakes? You can get away with only 3 x 3/4 " pipes but lots put 4 x 3/4" pipes on for intakes. What ever size you go with step up your valve size by 1/4 " example 3/4 pipe 1" valve to keep inside valve larger. I used a gate valve on mine so I could count turns as to looking at leaver on a ball valve. The build is what ever you want it to be. Good luck with your build and happy smoken oh send some pic. when you get er done.

landshark530
10-10-2015, 08:30 AM
As an option...
If your hole gets out of hand just use car exhaust pipe and rtv caulk to seal it all up. Saved a lot of struggle when I blew the hole out.

http://www.bbq-brethren.com/forum/showthread.php?t=48042

bvbull200
10-10-2015, 08:30 AM
Two 3/4" intakes plus one 1" intake with a ball valve is plenty of intake.

Fwismoker
10-10-2015, 09:27 AM
Two 3/4" intakes plus one 1" intake with a ball valve is plenty of intake.
What might be plenty for you won't be for others. Different altitudes and weather climates and on top of that some want to cook hot enough for pizzas etc...


My philosophy is the more the better because you can close off what you don't want or need....Why limit yourself?

bvbull200
10-10-2015, 10:45 AM
What might be plenty for you won't be for others. Different altitudes and weather climates and on top of that some want to cook hot enough for pizzas etc...


My philosophy is the more the better because you can close off what you don't want or need....Why limit yourself?

How much intake do you have? Why not add more?

I get the sentiment, but it isn't like anyone is going to recommend surrounding the entire bottom of the drum with intakes. The circumference is a little over 72", are you going to suggest 72 inches worth of intake for his drum? If not, why limit him?

We've built drums with three 3/4" intakes, two 3/4" intakes and a 1" intake, four 1" intakes, two 3/4" intakes and two 1" intakes, and various other configurations. From outside temps from 20* - 110*, it always ends up being one 3/4" fully opened and a 1" ball-valve partially closed (or the equivalent) for temps up to 400*+. With an extra 3/4" intake to open and some play left with the ball-valve, there is plenty of headroom.

The curve for diminishing returns on these drums is pretty steep.

Fwismoker
10-10-2015, 11:28 AM
How much intake do you have? Why not add more?

I get the sentiment, but it isn't like anyone is going to recommend surrounding the entire bottom of the drum with intakes. The circumference is a little over 72", are you going to suggest 72 inches worth of intake for his drum? If not, why limit him?

We've built drums with three 3/4" intakes, two 3/4" intakes and a 1" intake, four 1" intakes, two 3/4" intakes and two 1" intakes, and various other configurations. From outside temps from 20* - 110*, it always ends up being one 3/4" fully opened and a 1" ball-valve partially closed (or the equivalent) for temps up to 400*+. With an extra 3/4" intake to open and some play left with the ball-valve, there is plenty of headroom.

The curve for diminishing returns on these drums is pretty steep.

No reason to have holes all the way around the drum for sure. I just know it's nice having more....the BP kit is one of my drums and it uses eight 3/4" holes of intake. It's nice for a variety of reasons including if i want to grill from a distance really hot, sear with the basket up high very hot and also for starting it up and getting the fire stoked quicker.

I have a little jumbo sized mini and it too has a ton of air intake. The primary air is from the bottom but it gets stupid hot for things like pizzas 550-700* I'll open all the air up initially for when i have a bunch of cold meat and was recently cooking 450* -500* with 44 lbs of cold pork butts minutes after putting the meat in. After the meat started coming up to temp then the air got cut back.

When you look at the fuel side of things some like to have small fires really hot vs more lit fuel which is not as hot for the same temps.

It's just nice having the air there if you need it is my thoughts on it. Also some folks will be cooking in below zero blustery Winter conditions, rainy climates and higher elevations so better intake/exhaust is a bonus.

bvbull200
10-10-2015, 12:22 PM
So the philosophy isn't to not limit yourself, it is to not limit yourself to less than YOU think.

As explained, what I suggested does leave more air if you need it. About twice as much, actually. Nothing you said indicates it is limiting at all.

Anyone reading this forum in somewhat extreme (for cooking) climates or elevations would do well to take all advice under consideration with their circumstances in mind.

bvbull200
10-10-2015, 12:50 PM
I bought this hole saw at Ace Hardware and it would cut a exact hole for $15 , the drill bit in the middle helps guide it but I do not know what size you need but just ask them . ignore the other stuff in my pic :wink:

http://img.photobucket.com/albums/v199/TwiztidOne/Brinkmann%20Cimarron%20Offset%20Smoker/DSCF6244.jpg

How many holes would you guess you could cut in a drum with that thing? I wear out step-bits like crazy. I figured the same would happen with a hole saw, but maybe I'm assuming too much.

mikemci
10-10-2015, 01:36 PM
You could completly perforate a drum without dulling a good hole saw. I personally don't like using a hole saw on thin metal. The pilot bit doesn't hold well in the drum and the saw will wobble. Then your hole is too sloppy to get a tight fit with the nipple.

Joe Black
10-10-2015, 06:57 PM
I bought this hole saw at Ace Hardware and it would cut a exact hole for $15 , the drill bit in the middle helps guide it but I do not know what size you need but just ask them . ignore the other stuff in my pic :wink:

http://img.photobucket.com/albums/v199/TwiztidOne/Brinkmann%20Cimarron%20Offset%20Smoker/DSCF6244.jpg

A good bi-metal hole saw will easily cut several holes in a drum. With a variable speed drill, you should be able to keep the speed slow and cut a clean hole. However, with all that having been said, drill a little larger hole to make your job easier. Then, use two pipe lock washers as shown in the pic above. In my work, we do this all the time. No problem. Good luck, Joe

BBQ Freak
10-10-2015, 09:36 PM
How many holes would you guess you could cut in a drum with that thing? I wear out step-bits like crazy. I figured the same would happen with a hole saw, but maybe I'm assuming too much.

I have drilled two holes trough 1/4" steel and it cut through them like butter and it did not wobble , very clean round cut .